JPS5957810A - Screw feeder - Google Patents

Abstract

PURPOSE:To prevent pulsative discharge so that uniform discharge is carried out in a screw feeder having an number threads, by constituting such that the area of the dicharge port end part of the feeder is gradually increased over minimum 1/n pitches in the discharge port end. CONSTITUTION:A rectifying means comprising 4 thread coils is disposed in the vicinity of the discharge port end of a feeder, and the discharge end port part 6 of a screw 3 is faced to the discharge port end so that the area of the discharge port end part 6 is gradually decreased. In this arrangement, in the case of providing n screw threads, the area is gradually decreased over 1/n pitches. With this arrangement pulsative discharge which has been unavoidable to conventional screw feeders may be prevented, and therefore, uniform discharge may be made.

Description

[Detailed Description of the Invention] Does the present invention provide pulsating discharge due to the pitch of the screw special M? This relates to a screw feeder that allows for uniform discharge.

Currently, screw feeders are widely used in general traps, but it is not possible to make the discharge uniform when lifting using the discharge characteristics of the screw as is, and when trying to achieve uniformity, the following methods are recommended. measures are being taken.

(1) Install a v3a shielding plate or rectifying plate such as a grid plate at the tip of the tweeter outlet. In this case, there is a drawback that the load changes suddenly when the discharge speed (rotation speed) is changed.

(2) Remove one to several pitches of screw blades from the feeder outlet end. In this case, both the load and the amount left behind become large, and uniform discharge may not always be possible depending on the physical properties of the powder or granules.

(3) Make the number of turns of the screw two to several. This case has the disadvantage that the load increases rapidly as the number of turns increases.

Therefore, the purpose of the present invention is to reduce
4j4 to eliminate unavoidable pulsating discharge and ensure uniform discharge.
Q
be.

According to the present invention, in a screw feeder having an n-threaded screw (where n is 1 or more), the above-mentioned object is achieved by configuring that the area of at least one of the screws at the discharge end of the screw is gradually reduced. can be achieved. In particular, it is preferable to provide a means for straightening the granular material discharged adjacent to the screw at the discharge end of the screw.

[The screw feeder of the present invention is shown in attached drawing K7J]
This will be explained in detail below using an example.

The screw of the screw feeder has a uniform shape around 9 of the m moving ql+. The reason for this is that unavoidable pulsation occurs, and conventional methods for solving this problem have not yielded satisfactory results.

Therefore, in the present invention, as shown in FIG. 11, the end portion of the screw discharge port of the screw feeder is made to have an area that gradually decreases. That is,
In Fig. 1, 1 is a casing, 2 is a drive shaft disposed inside the casing, 3 is a screw wound around the drive shaft, 4 is a discharge port, and 5 is a four-strand coil 4'i.
& I have the rectification means mentioned. Although the discharge port 4 can be formed as shown in FIG. 2, it is not necessarily limited thereto. Further, although the rectifying means 5 is constructed of four metal coils C, it is not necessary to provide them, and it goes without saying that it can be of any other suitable construction.

Now, the discharge port end portion 6 of the screw 3 is shown in FIG.
As shown, the area gradually decreases as it approaches the end of the discharge port. The screw portion 6 whose area is gradually reduced will be explained with reference to FIG. 4, which schematically shows it. Figure 4a shows the screw part 6 whose area gradually becomes smaller.
As you can see, the first diagram is a graph showing the area of f. The area of the end OC of the screw is OQ, and the area from there at the angle (σ) in the winding direction of the screw is n71:, 2nπ
It increases linearly as shown by the position. Although the area reduction ratio does not necessarily have to be linear as shown in Figure 4b, it is preferred for manufacturing and emission control reasons.

As a result of experiments, it has been found that the length of the screw portion 6 whose area should be reduced is preferably one to several pitches, but the F limit is preferably one pitch to obtain a satisfactory result. . The area below 1 pitch can be defined as the area decreasing area. (Although it is good to set the upper limit to 1 pitch.The upper limit is also related to the overall length of the screw, so it varies depending on the screw feeder. Therefore, Preferably, the screw portion 6 whose area is to be reduced is at least one pitch from the outlet end.

In some cases, the above theory has one thread, but it is also possible to have n threads (n is an integer of 1 or more), and in this case, in order to achieve a satisfactory result, the above Preferably, the area of the tapered area is at least -bit.

Next, the powder discharge characteristics of a screw feeder with a screw feeder that has an area that gradually decreases at the end of "non-explosion" and a conventional screw feeder that has a screw with a uniform area are shown in the fifth section.
As shown in the figure. In Fig. 5, the upper stage C1 (a) shows the change in the discharge amount per one rotation of the screw. Figure 5C is the fifth above.
a shows the emission characteristic curves of FIGS. 46 and 5b; FIG. It is well understood that the discharge characteristic curve 1 of the screw feeder of the present invention has no pulsation compared to that of the conventional screw feeder.

As is clear from the above explanation, the screw feeder of the present invention can substantially eliminate the discharge pulsation that always occurs in conventional screw feeders by gradually reducing the area of the discharge end portion of the screw by at least one pitch. There is no need to provide additional means for eliminating pulsation, the structure is simple, and the effect is great. The screw feeder of the present invention enables precise quantitative discharge regardless of the type of powder or granular material, and can be used in FC under a wide range of operating conditions.It can be used for various types of no-doling, is easy to control, and can cover a wide range of discharge amounts. It is easy to use and can be applied to the system as an automatic control device.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional view of the screw feeder of the present invention;
FIG. 2 is a bottom view of the same, FIG. 3 is an end view of FIG. 1 as seen from the river exit direction, and FIGS. 4a and 4b are schematic diagrams 6 and 4 showing the gradual decrease in the area of the screw, respectively. Graph showing,
Figures 5a and 5b show the rotational modes of the conventional and inventive screw feeders, respectively.
The figure is a graph showing the discharge characteristics of powder and granular material depending on the rotation mode shown in Figures 5a and 5b. Explanation of symbols 1--Casing, 2--Drive shaft, 3--Screw, 4--Discharge port, 5--Rectifying means, 6--Area ilυ1 reduced portion Patent applicant Nisshin Seifun Co., Ltd. Figure 1 Figure 2

Claims (2)

[Claims] (1) In a screw feeder having n screws (n is an integer of 1 or more), the screw is
A screw feeder characterized in that the discharge end is configured such that the area thereof is gradually reduced at least in pitch. (2) In a screw feeder having n screws (n is an integer of 1 or more), at least the upper pitch of the discharge end of the front AI2 screw is rfi fN '1
1. A screw feeder configured to gradually decrease the flow, and characterized in that a flow straightening means is disposed downstream of the screw and adjacent to the screw.